Vegetable sales rocketed 250 per cent in a Japanese supermarket where tomatoes, broccoli and corncobs talked to shoppers, website What Design Can Do reports.

When touched, the veggies gave their own traceability information in the voice of the farmers that grew them, it said.

The in-store promotion tool called ‘Talkable vegetables’, developed by advertising agency Hakuhodo and a specialised lab, makes use of the voltage differential between the moist of human hands and the vegetables: touching a tomato works as switch that sets of an audio signal, the site said.

The tool was used to inform customers on the produce’s safety and trustworthiness, and the environmental and other farming values under which the vegetables were grown.